Regular blood transfusion therapy is the standard care for secondary prevention of strokes in sickle cell disease (SCD). Despite regular blood transfusion therapy approximately 45% of the children with strokes will have progressive neurological disease (overt strokes or new silent cerebral infarcts) with an incidence of overt strokes of 3.2 events/100 patient-years (95% confidence interval, 1.3-6.5) (Hulbert, Blood 2011). Limited additional therapeutic options exist for these patients. Encephaloduroarteriosynangiosis (EDAS) is a neurosurgical procedure to improve cerebral blood flow by transposing scalp arteries onto the surface of the brain. Five previously published series reported a total of 41 EDAS or indirect revascularization procedures on patients with SCD aged 3-22 yrs. Three of 41 patients (7%) had a stroke at 24 hours, 5 days and three weeks following EDAS/indirect revascularization. Additionally, one patient developed TIA 12 months later, two patients developed intracranial hemorrhage, and one patient died from a pulmonary embolus during an episode of acute chest syndrome 48 months post-EDAS. To date, the incidence of complications and efficacy of EDAS procedure in stroke prevention has not been well established.
To examine the incidence of overt stroke pre and post-EDAS for patients on chronic transfusion.
We studied a pediatric cohort with history of HbSS and SB0 thalassemia on chronic transfusion for CNS injury who underwent EDAS at the University of Alabama at Birmingham. The incidence of overt stroke pre- and post-EDAS was reviewed. All pre-transfusion hemoglobin and percent Hemoglobin S levels were recorded from the time of their first recorded abnormal MRI. To determine the acute complications of EDAS, we reviewed the peri-operative hospital records at the time of EDAS, post-EDAS emergency room visits and chronic transfusion clinic visits post EDAS.
A total of 13 patients on chronic transfusion for secondary stroke prevention underwent 17 EDAS procedures for recurrent stroke, progressive vascular disease, or neurologic change including psychosis and decline in neuropsychometric scores. The mean time to EDAS was 80 months (median 56) from their first abnormal MRI in the medical records. The patients’ mean pre-transfusion hemoglobin level was 9.4 g/dL and mean HbS was 29.5%. All participants (n=13) maintained a mean pre-transfusion HbS < 40%; 62% (8/13) participants maintained a mean HbS <30% (two patients with elevated HbS were transitioned to hydroxyurea as part of a clinical trial). Prior to EDAS, three patients had a new overt stroke during 81 patient years.(3.7 strokes per 100 pt yrs) One of 17 EDAS procedures was complicated by an acute stroke one month after the procedure. No additional strokes occurred in these patients during 34 patient years.(3 strokes per 100 pt yrs) One child developed a chronic subdural hematoma one month post-EDAS requiring burr hole drainage; this patient had a complete recovery.
This case series represents the largest cohort of EDAS procedures for children with SCD, and in combination with the literature, suggests that patients with progressive CNS disease may benefit from EDAS. A multicenter retrospective case series should be completed to identify risk factors for progression status post an EDAS procedure followed by a clinical trial to determine the effectiveness of the procedure versus regular blood transfusion therapy.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.